Bamboo Panel Boards
a State-of-the-Art Review
Technical Report No. 12

P.M. Ganapathy
c/o Indian Plywood Industries Research and Training Institute
Bangalore, India

Zhu Huan-Ming
Research Institute of Wood Industry, Chinese Academy of Forestry
Beijing, China

S.S. Zoolagud
Indian Plywood Industries Research and Training Institute
Bangalore, India

D. Turcke
Department of Civil Engineering, Queen’s University
Kingston, Ontario, Canada

Z.B. Espiloy
Forest Products Research and Development Institute
College, Laguna, the Philippines

International Network for Bamboo and Rattan
Beijing

New Delhi

 Eindhoven

International Network for Bamboo and Rattan, 1999
All rights reserved. No part of this publication may be reproduced or transmitted
in any form or by any means, electronic or mechanical, including photocopy,
recording or any information storage and retrieval system, without permission in
writing from the publisher.
The presentation of material in this publication and in maps that appear herein
does not imply the expression of any opinion on the part of INBAR concerning
the legal status of any country, or the delineation of frontiers or boundaries.

ISBN

81-86247-28-9


CONTENTS
FOREWORD
1 INTRODUCTION
2 BAMBOO PANEL PRODUCTS: AN OVERVIEW
Types of Boards
Boards from slivers, strips or laths
Boards from veneer
Boards from reconstituted particles, strands or fibers
Composite boards
National Standards
Commercial Production
Further Information and Contacts
3 AN APPRAISAL OF BAMBOO PANEL BOARD TECHNOLOGIES
Technologies Developed
Bamboo mat board

Corrugated roofing sheet
Parallel gluelam
Parallel curved gluelam
Bamboo curtain board
Bamboo strip board
Bamboo lath board
Bamboo “zephyr” board
Bamboo net board
Bamboo moulded products
Plybamboo
Particleboard
Bamboo mat and bamboo curtain board
Bamboo mat and bamboo particleboard
Bamboo mat wood veneer board
Bamboo mat/curtain with wood veneer
Bamboo mat overlaid particleboard
Bamboo mat overlaid rice husk board
Bamboo strip and wood veneer
Bamboo strip, bamboo particle and wood veneer

1
3
4
4
5
5
5
6
7
8

10
10
10
22
23
24
25
26
29
31
31
31
33
34
38
38
39
39
39
39
40
41


4

Veneer overlaid bamboo slivers moulded beating club
Cement-bonded bamboo particleboard
Gypsum-bonded
particleboard

Bamboo particle plaster board
Technologies Being Experimented
Bamboo oriented strand board
Arc-shaped decorative board
Bamboo fiber reinforced plastic

41
41
42
43
43
45
45
45

CONCLUSION

46

FURTHER READING
ANNEXES
1 Proforma used for gathering information
2 Profiles of selected bamboo panels
Bamboo mat plywood
Bamboo mat board
Bamboo sliver laminated board
Bamboo curtain plywood
Bamboo strip plywood/Bamboo plywood
Bamboo strip board
Bamboo particleboard

Bamboard
3 The State Standard of the People’s Republic of China:
Bamboo Mat Plywood
4 The Forestry Standard of the People’s Republic of China:
Bamboo Strip Plywood for Automobile Carriage Base Plates
5 Indian Standard Specification for Bamboo Mat Board for
General Purposes
6 Preliminary Draft Indian Standard Specification for
Bamboo Mat-Wood Veneer Composite for General Purposes

48
55
55
59
59
60
61
62
63
64
65
66
67
75
93
105


FOREWORD
In the search for non-timber forest products to substitute for wood, bamboo

has emerged as a material par excellence. It is now widely recognized that bamboo
in panel form is ideal to replace wood in several applications. Because of this,
the Research Advisory Group of the International Network for Bamboo and Rattan
accorded high priority for research on bamboo based panels and recommended
that a review of existing bamboo panel products and technologies be undertaken
as a step to determine future research needs. Bamboo Panel Boards: a State-ofthe-Art Review is the result of that recommendation. The Indian Plywood Industries
Research and Training Institute was nominated as the lead institution for the study.
FORINTEK Canada, the Chinese Academy of Forestry, and the Forest Products
Research and Development Institute of the Philippines collaborated in the effort.
The first bamboo-based panel was produced in China in the 1940s. Since
then, some 28 panel products have been developed. Among the technologies
developed, only a few, like bamboo mat board and bamboo strip board, are the
outcome of detailed investigations and industry-scale trials. Others are mostly
based on limited laboratory experimentation and industrial testing. Hence, the
commercialization of bamboo panels is not commensurate with the variety of
products developed. Furthermore, countries in which the panels are produced have
not accorded a distinctive status to them, and statistics of their production and
trade are incomplete or unreliable. This makes it difficult to assess the potential,
but the level of interest provides pointers. For instance, in China, about 100 000 m3
of panels of various types are produced annually in some 200 mills, whereas in
India, industrial-scale production of panels is confined to bamboo mat board with
about 2 000 m3 boards produced by seven mills.
To ensure that all relevant published data are included, a literature review
was conducted using advanced search methods and reference to forestry and
forest products databases. However, much information on technologies is
unpublished and the authors had to depend on personal communications and visits
to laboratories.
We hope that all scientists and institutions concerned, in Asia and other parts
of the world, will find the information contained in this report useful for their work.
I.V. Ramanuja Rao

Senior Manager (Programs)

Cherla B. Sastry
Director General


INTRODUCTION
Since research on bamboo is of relatively recent occurrence, the potential of
this versatile material has remained largely unexploited. Although wide-ranging
research has been carried out on the structure, properties and preservation of
bamboo, the results have hardly been applied by engineers and architects.
In the 1980s on account of dwindling wood supplies in the tropics, interest
in bamboo as a material intensified. It emerged as the most potentially important
non-timber forest product to replace wood in construction and other uses. The
realization that bamboo produces woody biomass faster than most fast-growing
trees, and that some of its properties rival those of juvenile wood obtained from
such species, has evoked keen interest in theoretical and practical research on
bamboo as a wood substitute in housing, furniture, packing, transport and other
fields.
Bamboo in panel form is well suited to substitute wood and therefore,
development/refinement of cost-effective technologies to produce bamboo-based
panels is an important area of research. In 1990, the International Development
Research Centre of Canada commissioned an evaluation on past research and
research needs for bamboo and rattan. The report issued in 1991 indicated the
need for further attention on bamboo panels.
Although the environmental and socio-economic implications of bamboobased panel industries favor their promotion, neither detailed environmental impact
assessment nor socio-economic impact assessment of these industries has been
carried out. Nonetheless, it is tentatively reckoned that if bamboo mat boards
replace plywood to an extent of one-fourth the present production in India,
400 000 m3 of round wood from natural forests will be saved, thereby preventing

disturbance to 30 000 ha of forests per year. It is also estimated that production
of mats to manufacture this quantity of mat board will generate 16.7 million
workdays of employment per year. In China, approximately 1 million cubic meters
of wood are replaced annually by various types of bamboo panels.
When the International Network for Bamboo and Rattan (INBAR) was being
formally established, a network meeting was held in June 1993 which endorsed
the need for a review of the status of bamboo panels and boards. Accordingly,
INBAR commissioned a study and this report is the result. The review involved:


2
BAMBOO

PANEL

BOARDS

gathering information(Annex
1); preparation of a draft report based on information
gathered; circulation of the draft among collaborating scientists for comments; and
finalization of the report.
Apart from the contributions of scientists from the collaborating institutes,
several others in the panel-producing countries provided valuable insights that
have gone into this report. In particular, thanks are due to: Mr. Dao Viet Phu, Dr
Haong Van Hien, Dr Hartoyo, Dr Hsiu-Hua Wang, Dr H.N. Jagadeesh, Dr Abd.
Latif Mohmod, Dr Sheau-Horng Lin and Mr. Sounthone Ketphanh.


BAMBOO PANEL PRODUCTS:
AN OVERVIEW

The first recorded production of bamboo-based panels was in China. During
World War II, a simple technology was developed in China to manufacture bamboo
mat board bonded with casein glue, for use as alternate to plywood in the interiors
of aircrafts. At about the same time, research was initiated in India to develop
resin-bonded bamboo mat board; technology became available about a decade
later. Since then, research has been carried out in several countries and as many
as 28 panel products - some of bamboo and others of bamboo in combination
with wood and/or inorganic materials - have been developed. While R&D efforts
have been mostly confined to Asia (China, India, Indonesia, Laos, Malaysia, the
Philippines, Taiwan-China, Thailand and Vietnam), Canada, in collaboration with
Costa Rica, has also carried out research on bamboo boards.
China has developed the maximum number of panel products, although many
of these are based on commercially uncertain technologies. The growth of bamboo
panel board industries in China is related to two factors. First, there were
inadequate supplies of raw material. The growth rates and harvesting cycles of
temperate bamboo are longer than that of tropical species. Hence, despite the
large area under bamboo, availability of culms is low. Moreover, traditional and
established uses - such as handicrafts, basketry, chopsticks and poles - compete
with use for boards. Second, costs associated with bamboo are steadily increasing,
throwing the economics of panel manufacture out of gear.
Although some pioneering work was done and innovative products like
plybamboo (bamboo veneer-faced plywood) and lamboo (parallel curved bamboo
gluelam) were developed in Taiwan-China, the bamboo board industry in this
region is declining since the sharp increase in wages and raw material shortage
are causing the manufacturers to emigrate elsewhere.
In India, although several products have been developed, bamboo mat board
is the only one that has attracted entrepreneurs and gained user acceptance. In
Thailand, bamboo mat board glued with urea-formaldehyde (UF) resin is being
manufactured, mainly for export. In countries such as Laos, the Philippines and
Vietnam, interest on bamboo board is recent and still experimental or at the level

of pilot production.


4
BAMBOO

PANEL

BOARDS

As bamboo panel products have not been accorded uniformly distinctive
categorization in compilation of statistics, reliable production data are not available.
Absence of reliable production and market statistics is a severe handicap in
evaluating the current status and future prospects of bamboo boards. Projections
have, however, pointed out the important role of bamboo boards in view of
diminishing wood supplies.
In the absence of standard test methods and generation of standardized
information on properties, such as those that exist for wood-based panels, data
for individual products are presented in the way in which they were reported. Until
test methods are standardized and format of reporting data on properties and
performance harmonized, it would be difficult to accurately compare products
manufactured in different regions or countries. In this respect, Annex 2 provides
data on some products, as a step towards standardization.

Types of Boards
Based on the culm derivatives used, the boards may be grouped in the following categories:
Culms converted into slivers, strips or laths by flattening and/or cutting, and
further processed;



. Culms peeled into veneers and further processed;


Culms converted into particles, fibers, wafers or strands and reconstituted; and

Combination of one or more of above products among themselves or with
other materials and further processed (termed in this report as composites). Such
composites include: different bamboo panels; wood or other lignocellulosic materials; and inorganic substances.


Boards from slivers, strips or laths
Slivers of uniform thickness and width are woven into mats, following traditional or innovative designs and cold or hot-pressed into boards to produce:
Bamboo mat board
Vietnam.
Corrugated sheet

In China, India, the Philippines and
Surface finished or laminated in China,
India, the Philippines and Vietnam for use
in roofing.

Strips/slivers assembled in layers and bonded under pressure to produce:
Parallel gluelam
Parallel curved gluelam (lamboo)
Bamboo curtain board

To a limited extent in China.
In Taiwan-China region for furniture.
In China.



BAMBOO

PANEL

Bamboo strip board/bamboo plywood

BOARDS

In China, and also to a small extent in
Costa Rica, Malaysia, Taiwan-China and
Vietnam.

Bamboo lath board/bamboo block board In Indonesia on an experimental scale.
A product simulating “zephyr” wood, in
Bamboo “semi-fiber” board
which culms are crushed under pressure
and assembled in layers and hot-pressed
(experimental scale in Indonesia).
Bamboo net board
Bamboo moulded shuttle &
picking stick

In limited quantity in China.
In restricted quantity in China.

Boards from veneer
Plybamboo

A highly decorative product, in which

rotary-cut bamboo veneers are used as
face and wood veneers or blocks as
core, is produced at present in small
quantities in China.

Boards from reconstituted particles, strands or fibers
Bamboo

particleboard

Largely following technology employed
for wood particleboard, bamboo particleboard has been developed in Canada (in
collaboration with Costa Rica), China,
India and Vietnam. Although the product
is comparable to wood particleboard in
properties and performance, production
is limited as the technology is yet to
overcome some inherent problems of
bamboo.

Oriented strand board

Research is reported in Vietnam.

Bamboo fiberboard and
medium density fiberboard (MDF)

Research in progress in China and India.
A small quantity is produced in China.


Composite boards
Bamboo mat/bamboo curtain board
Bamboo mat/bamboo particleboard
and India.

Developed in China.
Produced in small quantities in China

Plybamboo

(See information provided earlier).


6
BAMBOO

Bamboo

PANEL

BOARDS

Bamboo mats are used as face and
wood veneers as core. A popular
product in China and India.

plywood

Bamboo curtain plywood


Bamboo curtain board is used as face
and wood veneers as core. Small
quantity produced in China.

Bamboo mat and wood particleboard

Bamboo mat is used as face and wood
particleboard as core. Produced in
limited quantity in China.

Bamboo mat and rice husk board

Bamboo mat is used as face and rice
husk particleboard as core. Produced
in small quantity in India.

Bamboo strip, wood veneer and
particleboard

Bamboo strip board forms the face.
Wood veneer and particleboard are
used as core.
A tough product, in which bamboo
sliver and wood veneer are bonded.
Made in very small quantity in China.
Produced on an experimental scale in
the Philippines.

Bamboo moulded shuttle beating club


Gypsum-bonded bamboo particleboard
Cement-bonded
wool board

particleboard

Bamboo plaster board
Bamboo reinforced plastic

and

Produced on an experimental basis in
China. The former is produced in
Malaysia also.
An innovative product being developed in
China.
A high-tech material under experimentation in India. Bamboo fiber reinforced
plastic sheets are being developed.

Of the above types of boards, only bamboo mat board (a bamboo panel that
has shown maximum promise) and bamboo strip board have been exploited on
an industrial scale and products marketed for various end-uses. Other technologies
are either in various stages of development or only at the initial stages of
experimentation. Further research is foreseen in these cases.

National Standards
National Standards have been formulated in China for bamboo mat plywood
(Annex 3) and bamboo strip plywood for automobile carriage base plates (Annex 4),
and in India for bamboo mat board for general purposes (Annex 5). A Draft Standard
exists in India for bamboo mat-veneer composite for general purposes (Annex 6).

Both China and India have standards on test methods for bamboo mat board.


7
BAMBOO

PANEL

BOARDS

Commercial Production
The panels for which technology is developed and commercialized or awaiting
commercialization are listed in Table 1.
Table 1: Panels commercialized or ready for commercialization
Panel

Country
China

Costa

Mat board (locally known as bamboo mat plywood)
Corrugated roofing sheet
Parallel gluelam
Curtain board (known as curtain plywood)
Strip board (locally known as bamboo strip plywood or
bamboo plywood)
Lath board (laminated lumber)
Plybamboo
Particleboard

Mat and curtain board
Mat and bamboo particleboard
Mat and wood particleboard
Mat and wood veneer (locally known as bamboo plywood)
Bamboo mat/curtain board and wood veneer
Plastic overlaid bamboo particleboard
Moulded shuttle and picking stick
Cement-bonded particleboard and wool board
Plasterboard
Rica/Canada Strip board (termed Plybambu)
Particleboard (termed Barnboard)

India

Indonesia

Lao PDR
Malaysia

The Philippines

Bamboo mat board
Particleboard
Mat with wood particleboard
Mat with wood veneer
Mat with rice husk
Lath board (Blockboard)
Semi-fiber board (Zephyr)
Cement-bonded
particleboard

Mat board
Curtain board
Particleboard
Cement-bonded
Gypsum-bonded

particleboard
particleboard


8
BAMBOO

PANEL

Country

Panel

Taiwan-China

Parallel curved gluelam
Curtain board
Plybamboo

Thailand
Vietnam

Mat board
Mat board

Corrugated roofing sheet
Curtain board
Particleboard

BOARDS

Further Information and Contacts
Most of the above products are manufactured by small-scale enterprises and
very few responded to requests for information. Hence, the authors had to resort
to existing trade literature, direct personal contacts with manufacturers, and/or
indirect contacts with traders or laboratory personnel. More information on products may be obtained from the contacts cited below.
CHINA
Prof. Zhu Huan-Ming, Research Institute of Wood Industry, Chinese Academy
of Forestry, Nan Shen Shan, Beijing 100091.
Tel: +86 (10) 62582211, Ext. 413; Fax: +86 (10) 62581937.
COSTA RICA
Ing. Eduardo Barquero, Director, CIVCO, Apdo. 159-7050, Cartago.
Tel: +506 5518220; Fax: +506 5516663.
INDIA
Dr S.S. Zoolagud, Scientist, Indian Plywood Industries Research & Training
Institute, P.B. No. 2273, Tumkur Road, Bangalore 560 022.
Tel: +91 (80) 8394231; Fax: +91 (80) 8396361.
INDONESIA
Dr Hartoyo Wardi, Secretary, Agency for Forestry Research and Development,
Ministry of Forestry, Manggala Wanabakti Building, JI. Gatot Subroto, Jakarta.
Tel: +62 (21) 583033/37; Fax: +62 (21) 5737945.
LAO PDR
Dr Southane Ketphanh, Principal Researcher, Forest Products Division of
Nature Conservation & Watershed Management, Ministry of Agriculture and
Forestry, PO. Box 844, Vientiane.

Tel: +85 (6) 3807, 5539; Fax: +85 (6) 3807.


9
BAMBOO

PANEL

BOARDS

MALAYSIA
Dr Abd. Latif Mohmod, Senior Research Officer, Forest Research Institute
Malaysia, Kepong, Kuala Lumpur.
Tel: +60 (3) 6242633; Fax: +60 (3) 6367753.
THE PHILIPPINES
Dr Z.B. Espiloy, Supervising Science Research Specialist, Forest Products
Research and Development Institute, College, Laguna 4031.
Tel: +63 (94) 3630, 2377, 2586; Fax: +63 (94) 3630.
TAIWAN-CHINA
Dr Hsiu-Hwa Wong, Department of Forest Products Technology, National
Pingtung Polytechnic Institute, Pingtung.
Tel: +886 (8) 7701366; Fax: +886 (8) 7701366.


AN APPRAISAL OF BAMBOO
PANEL BOARD TECHNOLOGIES
Existing bamboo panel board technologies have resulted from:
1. Research, development and industrial-scale trials carried out in national
laboratories either under their own programs or donor assisted projects;
2. Research conducted in national laboratories and passed on to entrepreneurs for trial and adaptation; and

3. Development efforts of entrepreneurs themselves.
While the technologies developed and scaled up in research institutions are
mostly documented and/or published, those developed by entrepreneurs are seldom
published. Although all available information has been collated in this report, it is
scanty in a few cases, especially where individual entrepreneurs have made their
own modifications or held back information.
The following appraisal divides technology development into two groups:
technologies already developed and technologies still experimental.

Technologies Developed
Bamboo mat board (BMB)
BMB is the first bamboo-based panel to be produced commercially. Its versatility
has been widely recognized and further research is in progress to improve its
efficiency, enlarge its application potential and optimize production costs. It is commercially produced in China (under the name bamboo mat plywood), India, Thailand
and Vietnam, while laboratory-scale production is reported in the Philippines. The
technologies developed are described in the following pages.
CHINA

Casein glue-bonded BMB
The earliest boards produced were casein-bonded and their chief use was


11
B A M B O O

P A N E L

B O A R D S

for interiors of aircrafts. Only species with long internodes, such as Bambusa

textilis, were used. The steps involved in the manufacture of boards are:


















Separation of internodal segments;
Splitting into 5-6 mm wide strips;
Slitting of strips tangentially into slivers;
Selection of outer slivers with epidermal layer (for greater strength and
stiffness);
Weaving of slivers into mats, in different patterns;
Coating of casein to the under surface of slivers;
Assembly in two layers of mats or three layers, i.e., mat + wood veneer +
mat panels;
Cold-pressing; and
Trimming.


Resin-bonded BMB
Synthetic resin-bonded BMB was developed in the 1970s in China. Although
urea formaldehyde (UF), phenol formaldehyde (PF) and phenol-tannin formaldehyde (PTF) are employed as the bonding resin, UF-bonded BMB is the most
common. UF in this case is part of polymerization in three stages (70%, 20%,
10%) instead of two, as in the case of wood adhesives. The optimum gram molecule ratio for formaldehyde and urea is 1 :1 .6. Less commonly, alkali-catalysed PF
resin adhesive is used instead of UF. PTF resin, PF resin with phenol replaced to
the extent of 60% by tannin from larch bark, is also being successfully employed
in some cases. The stages in the manufacture of resin-bonded BMB are:
. Conversion of culms into strips and thereafter slivers of uniform width 1216 mm and thickness 0.6-l .2 mm, manually or mechanically. Elimination
of slivers with outer skin (epidermal layer);
Weaving of slivers of uniform size manually or mechanically into mats of
size 2 500 x 1 300 mm:
Drying of mats to 8-16% moisture content;
Coating or impregnation of glue (280-500 g/m2). Soybean flour is used as
filler to the extent of 510%. Ammonium chloride (NH4CI) of 0.5% concentration is used as curing agent;
Hot-pressing (temperature: 110-120°C for UF resin, 140-l 50°C for PF resin;
pressing time: 1.5-2 minutes/mm thickness; specific pressure: 4-5 MPa);

.

Laying up;
Curing; and
Trimming.
In the production of decorative mat boards, the slivers are sanded, bleached
and sometimes dyed. Two methods of bleaching are commonly practiced:


12
B A M B 0 0 I A N E I. B 0 A R D S


1. Soaking of slivers in 1% sodium hydroxide (NaOH) for 2-4 hours, followed
by soaking in 25% hydrogen peroxide for 5-10 hours. The slivers are thereafter washed in water and dried to 8-16% moisture content; and
2. Soaking of slivers in a solution of 1% oxalic acid and 0.5% NaOH for 1016 hours. The slivers are then washed in water and dried.
Dyeing or imparting attractive colors to the slivers using bright and durable
synthetic dyes is a common practice. Alternatively, the mat boards are treated with
sulphuric or nitric acid and baked immediately in fire to obtain black or brown-red
color, respectively, Mat boards are occasionally overlaid with sliced wood veneers
to manufacture decorative plywood. The physical and mechanical properties of
typical UF-bonded BMB produced in China are given in Table 2.
Tab/e 2: Physical and mechanical properties of bamboo mat board (China)
Properties
Density (kg/m3)
Internal bond strength (MPa)
Modulus of rupture (MPa)
Tensile strength (MPa)
Impact tenacity (J/cm2)

Common BMB Veneer-overlaid BMB
850
1.57
93.0
72.6
3.1

860
1.37
119.6
64.6
2.97


Fig. I: Dried mats being arranged for glue spreading


13
BAMBOO

PANEL

BOARDS

BMB (Figs. 1, 2) is used for packing, furniture and interior applications, such
as panellings and partitions. There are 16 factories manufacturing this panel and
the annual production is about 20 000 m3 {for standards, see Annex 3).

Fig. 2: Bamboo mat boards ready for packing and transport
INDIA
BMB technology development in India has undergone three stages, as described below.

Earliest technology
The first BMB produced in India was PF resin adhesive-bonded. The
technology involved:















Cutting of culms (with or without nodal portions) into pieces of 0.6 m length:
Splitting culms into strips;
Immersion of strips in boiling water for 1-2 hours;
Slitting of strips into slivers of uniform width and thickness (Fig. 3);
Separating outermost slivers with epidermal layer from innermost slivers,
used for other purposes;
Drying to 1 O-1 2% moisture content;
Weaving into mats of different patterns (Fig. 4);


14

Fig. 3: Slitting of strips into slivers

Fig. 4: Manual weaving of mats


15
BAMBOO








PANEL

BOARDS

Soaking in PF resin solution:
Seasoning to 1 O-1 2% moisture content;
Hot-pressing the assembled mats in 2, 3 or 5 layers for 20-30 minutes at
a specific pressure of 2.8-3.5 MPa; and

* Trimming (Fig. 5).

Fig. 5: Trimming of boards
Although the boards thus produced were attractive and strong, the technology
could not be commercialized because the cost of production was higher than that
for plywood.

Modified technology
In 1979, efforts were made to modify the technology mainly with the objective
of reducing production cost. Important modifications carried out were partial
replacement of phenol in PF resin adhesive, method of resin application, and
reduction of pressing time and temperature. In the adhesive, phenol was replaced
to the extent of 40% by Cardanol (a derivative of cashew nut shell liquid). The
Cardanol-phenol formaldehyde (CPF) resin adhesive thus developed was found
to give the required bond strength. The process steps were:





Drying of mats to 6-10% moisture content;
Spreading of resin adhesive (PF or CPF) on mat, using glue spreader
employed in plywood manufacturing;


16
BAMBOO





PANEL

BOARDS

Hot-pressing for 6 minutes (for 3-4 mm thick boards) at a temperature of
140-l 45°C and a specific pressure of 1.6 MPa; and
Open assembly over a period of 2-24 hours to reduce the moisture content of glue-spread mats to 15%.

The quantity of resin required was 1.3 kg/m2 of 3-layer board. The strength
properties of BMB thus developed are given in Table 3.
Table 3: Typical strength values of BMB bonded with PF and
CPF resin adhesives (India)
Resin type

Average strength values (MPa)
Internal bond strength

Surface


strength

Dry

Boil/Dry

Dry

Boil/Dry

PF

1.05

0.73

5.36

4.44

CPF

1.10

0.60

5.95

4.54


A factory in Kerala State started manufacturing BMB in 1984 using the
modified technology. This factory is still producing BMB, with slight modifications
of the process, and marketing it for use in furniture, housing and shuttering.
Entrepreneurial interest in the product, however, did not grow because of the
following problems:










High quantity of resin requirement (1.3 kg/m2 for 3-layer board) as compared with plywood (0.30-0.33 kg/m2 for 3-ply plywood);
Non-uniform bonding owing to glue starvation where slivers overlapped;
Blotches on faces of board caused by resin pushed to the surface during
hot-pressing;
Difficulty in separating panels from hot press; and
Low durability.

Improved technology
To overcome the above-mentioned problems, renewed efforts were made
under a project sponsored by the International Development Research Centre
(IDRC) of Canada. As a result, a much improved and cost-effective board was
developed. The technology has been standardized after pilot and factory-scale
trials. As testimony of maturity of the technology, seven units took up production
after the improved technology was released. Several more small-scale enterprises

are in various stages of establishment. An international team of experts mobilized
by IDRC expressed the view that the technology was suitable for adoption by other
countries. A training workshop was therefore organized with INBAR support in
which technologists from Bangladesh, Canada, China, India, Lao PDR, Malaysia,


17
BAMBOO

PANEL

BOARDS

Nepal, the Philippines and Thailand participated. In this workshop, the technology
was demonstrated and transferred. The improvements effected in the process are:
Reduction of PF resin quantity from 1.3 kg/m2 to about 0.3 kg/m*;







Better resin application method to ensure uniform bonding and surface
appearance;
Smooth release of panels from metal cauls; and
Increased durability imparted by incorporating a preservative in the glue.

The strength properties of BMB manufactured using the improved technology
are given in Table 4.

Table 4: Strength properties of BMB bonded with PF resin (India)
Properties
Density (kg/m3)
Internal bond strength (MPa)
- Dry state
- Wet state
Surface strength by torque wrench (MPa)
- Dry state
- Wet state
Tensile strength (MPa)
Compressive strength (MPa)
Modulus of rupture (MPa)
Modulus of elasticity (MPa)
Modulus of rigidity (MPa)

No. of mats used for making board
2

3

5

7

751

766

771


790

2.23
1.79

2.18
1.98

2.42
2.14

1.97
1.73

12.14
11 .01

11.42
11.42
22.69
16.77
50.74
3 678
5 881

11.23
10.47
26.59
30.35
56.31

3 220
6 050

9.47
9.10
29.54
35.30
59.35
3114
6 066

5 401

Another notable feature in the improved technology is the replacement of phenol
to the extent of 30-40% by lignin obtained from pulp mill effluent (black liquor).
The properties of BMB manufactured using phenol-lignin-formaldehyde (PLF) resin
adhesive are given in Table 5.
The improved manufacturing process involves the following steps:








Dipping the mats in PLF resin in which a preservative is incorporated. Mole
ratio of phenol, formaldehyde and sodium hydroxide is 1:2.2:0.18. The resin
spread is 0.11 kg PLF of 48% solids/m*, while dilution of resin with water
is in the ratio 1:2;

Drawing of excess resin;
Drying to 8-12% moisture content;
Hot-pressing for 6 minutes (3-layered board) at a temperature of 140-l 45°C
and a pressure of 1.6 MPa; and
Trimming.


18
B A M B O O

P A N E L

B O A R D S

Table 5: Strength properties of BMB bonded with PLF resin (India)
Properties

No. of mats used for making board
2
3
7
5

Density ( kg/m3)

782

826

775


847

internal bond strength (MPa)
- Dry state
- Wet state
Surface strength by torque wrench (MPa)
- Dry state
- Wet state

1.06
1.47

1.19
1.11

1.07
0.97

1.25
1.03

7.20
7.00

7.27
5.88

6.64
5.93


8.33
6.17

Tensile strength (MPa)

10.80

17.43

21 .18

26.18

Modulus of rupture (MPa)

19.85
40.09

23.38
43.97

25.00
4250

34.31
50.74

Modulus of elasticity (MPa)


3 119

3 087

2 679

3 095

Nail withdrawal strength (face) (N)
Screw withdrawal strength (face) (N)

350

1 005

1 660

1 750

2 300

2 535

3 025

3 325

Compressive

strength


(MPa)

At present, seven factories are manufacturing this product and the estimated
annual production is 2 000 m3. Standards are given in Annexes 5 and 6.
Some of the end-uses for which this panel is found suitable, in conformity to
relevant national standards, are:


Housing - doors (Figs. 6, 7), partitions, panelling, furniture, cladding;



Packaging - fruit packing cases (Fig. 8), ammunition boxes;





Storage - grain storage bins (both internal and external) (Fig. 9); and
Transport - bullock carts (Fig. l0), horse/mule drawn carriages.

THAILAND
BMB is being produced since 1985, mostly for export to European countries. UF
resin is used to bond mat board of l-10 mm thickness. At present, two factories are
producing the boards and each is following technology developed in-house. Vital
information is neither published nor readily disclosed. The boards are attractive, but
uses are limited on account of the resin employed. The process is as follows:









Conversion of culms into strips and thereafter slivers, mechanically;
Weaving of slivers into mats (both manually and mechanically) of various
attractive patterns;
Coating UF resin;
Hot-pressing;


I9

Fig. 6: Hollow-core flushdoor shutters

Fig. 7: Panel doors


Fig. 8: Apple packing case (compared with conventtonal case)

Fig. 9: Grain storage bins